Oral lactoferrin for the prevention of sepsis and necrotizing enterocolitis in preterm infants

Enteral lactoferrin supplementation for prevention of sepsis and necrotizing enterocolitis in preterm infants

BACKGROUND

Lactoferrin, a normal component of human colostrum and milk, can enhance host defenses and may be effective for prevention of sepsis and necrotizing enterocolitis (NEC) in preterm neonates.

OBJECTIVES

To assess the safety and effectiveness of lactoferrin supplementation to enteral feeds for prevention of sepsis and NEC in preterm neonates. Secondarily, we assessed the effects of lactoferrin supplementation to enteral feeds on the duration of positive-pressure ventilation, development of chronic lung disease (CLD) or periventricular leukomalacia (PVL), length of hospital stay to discharge among survivors, and adverse neurological outcomes at two years of age or later.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to update our search. We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2019, Issue 9), MEDLINE via PubMed (1966 to 20 January 2020), PREMEDLINE (1996 to 20 January 2020), Embase (1980 to 20 January 2020), and CINAHL (1982 to 20 January 2020). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.

SELECTION CRITERIA

In our search, we included randomized controlled trials (RCTs) evaluating enteral lactoferrin supplementation at any dose or duration to prevent sepsis or NEC in preterm neonates.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal and the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

Meta-analysis of data from twelve randomized controlled trials showed that lactoferrin supplementation to enteral feeds decreased late-onset sepsis (typical RR 0.82, 95% CI 0.74 to 0.91; typical RD -0.04, 95% CI, -0.06, -0.02; NNTB 25, 95% CI 17 to 50; 12 studies, 5425 participants, low-certainty evidence) and decreased length of hospital stay (MD -2.38, 95% CI, -4.67, -0.09; 3 studies, 1079 participants, low-certainty evidence). Sensitivity analysis including only good methodological certainty studies suggested a decrease in late-onset sepsis with enteral lactoferrin supplementation (typical RR 0.87, 95% CI, 0.78, 0.97; typical RD -0.03, 95% CI, -0.05, -0.0; 9 studies, 4702 participants, low-certainty evidence). There were no differences in NEC stage II or III (typical RR 1.10, 95% CI, 0.86, 1.41; typical RD -0.00, 95% CI, -0.02, 0.01; 7 studies, 4874 participants; low-certainty evidence) or 'all-cause mortality' (typical RR 0.90, 95% CI 0.69, 1.17; typical RD -0.00, 95% CI, -0.01, 0.01; 11 studies, 5510 participants; moderate-certainty evidence). One study reported no differences in neurodevelopmental testing by Mullen's or Bayley III at 24 months of age after enteral lactoferrin supplementation (one study, 292 participants, low-certainty evidence). Lactoferrin supplementation to enteral feeds with probiotics decreased late-onset sepsis (RR 0.25, 95% CI 0.14 to 0.46; RD -0.13, 95% CI -0.18 to -0.08; NNTB 8, 95% CI 6 to 13; 3 studies, 564 participants; low-certainty evidence) and NEC stage II or III (RR 0.04, 95% CI 0.00 to 0.62; RD -0.05, 95% CI -0.08 to -0.03; NNTB 20, 95% CI 12.5 to 33.3; 1 study, 496 participants; very low-certainty evidence), but not 'all-cause mortality' (very low-certainty evidence). Lactoferrin supplementation to enteral feeds with or without probiotics had no effect on CLD, duration of mechanical ventilation or threshold retinopathy of prematurity (low-certainty evidence). Investigators reported no adverse effects in the included studies.

AUTHORS' CONCLUSIONS

We found low-certainty evidence from studies of good methodological quality that lactoferrin supplementation of enteral feeds decreases late-onset sepsis but not NEC ≥ stage II or 'all cause mortality' or neurodevelopmental outcomes at 24 months of age in preterm infants without adverse effects. Low- to very low-certainty evidence suggests that lactoferrin supplementation of enteral feeds in combination with probiotics decreases late-onset sepsis and NEC ≥ stage II in preterm infants without adverse effects, however, there were few included studies of poor methodological quality. The presence of publication bias and small studies of poor methodology that may inflate the effect size make recommendations for clinical practice difficult.

The effect of breastmilk and saliva combinations on the in vitro growth of oral pathogenic and commensal microorganisms

Neonates are exposed to microbes in utero and at birth, thereby establishing their microbiota (healthy microbial colonisers). Previously, we reported significant differences in the neonatal oral microbiota of breast-fed and formula-fed babies after first discovering a primal metabolic mechanism that occurs when breastmilk (containing the enzyme xanthine oxidase) and neonatal saliva (containing highly elevated concentrations of the substrates for xanthine oxidase: xanthine and hypoxanthine). The interaction of neonatal saliva and breast milk releases antibacterial compounds including hydrogen peroxide, and regulates the growth of bacteria. Using a novel in vitro experimental approach, the current study compared the effects of this unique metabolic pathway on a range of bacterial species and determined the period of time that microbial growth was affected. We demonstrated that microbial growth was inhibited predominately, immediately and for up to 24 hr following breastmilk and saliva mixing; however, some microorganisms were able to recover and continue to grow following exposure to these micromolar amounts of hydrogen peroxide. Interestingly, growth inhibition was independent of whether the organisms possessed a catalase enzyme. This study further confirms that this is one mechanism that contributes to the significant differences in the neonatal oral microbiota of breast-fed and formula-fed babies.

Protocol for the Lactoferrin Infant Feeding Trial (LIFT): a randomised trial of adding lactoferrin to the feeds of very-low birthweight babies prior to hospital discharge

INTRODUCTION

Very-low birthweight (VLBW, <1500 g) infants comprise about 1%-1.4% of all births in high-income countries. Every year, about 3000 VLBW babies in Australia and New Zealand receive intensive care. Many die or else survive with severe brain injury, retinopathy, late-onset sepsis or necrotising enterocolitis (NEC), each of which carries substantial risk of disability.

METHODS AND ANALYSIS

This trial tests whether adding bovine lactoferrin (bLF) to feeds in VLBW infants improves (1) survival to hospital discharge free from brain injury, late-onset sepsis, NEC and treated retinopathy of prematurity (primary composite end point); (2) each component of the primary composite end point and (3) time to reach full enteral feeds, number of blood transfusions, chronic lung disease and length of hospital stay. It includes a cost-effectiveness analysis of bLF in improving survival free from major morbidity, and evaluates the effect of bLF on survival and developmental outcomes at 24 to 36 months corrected gestational age.This is a multicentre, two-arm, randomised trial comparing the treatment group receiving bLF added to breast milk or formula milk daily (up to 250 mg/kg/day bLF) versus the control group receiving no bLF supplementation. The intervention is administered until 34 completed weeks corrected gestation or for 2 weeks, whichever is longer, or until discharge home, if earlier. The target sample size of 1500 participants yields 85% power, at the two-sided 5% level significance, to detect a difference in proportions meeting the primary outcome assuming the true probability is 74% in controls and 80.5% in the bLF group.

ETHICS AND DISSEMINATION

This protocol was approved by Northern Sydney Local Human Research Ethics Committee in January 2017 (Version 2.0, Reference 1003-118M) and other relevant ethics committees. The findings of the trial will be disseminated through peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

ACTRN12611000247976; Pre-results.

Comparative Effectiveness of Prophylactic Therapies for Necrotizing Enterocolitis in Preterm Infants: Protocol for a Network Meta-analysis of Randomized Trials

Necrotizing enterocolitis (NEC) is a common and devastating disease with high morbidity and mortality in premature infants. Current literature on the prevention of NEC has limitations including lack of direct and indirect comparisons of available therapies. We will search MEDLINE, EMBASE, Science Citation Index Expanded, Social Sciences Citation Index, CINAHL, Scopus, ProQuest Dissertations and Theses database, and grey literature sources to identify eligible trials evaluating NEC preventive therapies. Eligible studies will (1) enroll preterm (gestational age <37 weeks) and/or low birth weight (birth weight <2500 g) infants, (2) randomize infants to any preventive intervention or a placebo, or alternative active or nonactive intervention. Our outcomes of interest are severe NEC (stage II or more, based on Bell's criteria), all-cause mortality, NEC-related mortality, late-onset sepsis, duration of hospitalization, weight gain, time to establish full enteral feeds, and treatment-related adverse events. Two reviewers will independently screen trials for eligibility, assess risk of bias, and extract data. All discrepancies will be resolved by discussion. We will specify a priori explanations for heterogeneity between studies. For available comparisons between treatment and no treatment, and direct comparisons of treatments, we will conduct conventional meta-analysis using a random effects model. We will conduct a network meta-analysis using a random effects model within the Bayesian framework using Markov chain Monte Carlo methods to assess relative effects of eligible interventions. We will assess the certainty in direct, indirect, and network estimates using the Grading of Recommendations Assessment, Development and Evaluation approach.

Enteral lactoferrin supplementation for prevention of sepsis and necrotizing enterocolitis in preterm infants

BACKGROUND

Lactoferrin, a normal component of human colostrum and milk, can enhance host defenses and may be effective for prevention of sepsis and necrotizing enterocolitis (NEC) in preterm neonates.

OBJECTIVES

Primary objective 1. To assess the safety and effectiveness of lactoferrin supplementation to enteral feeds for prevention of sepsis and NEC in preterm neonates Secondary objectives 1. To determine the effects of lactoferrin supplementation to enteral feeds to prevent neonatal sepsis and/or NEC on duration of positive-pressure ventilation, development of chronic lung disease (CLD) or periventricular leukomalacia (PVL), length of hospital stay to discharge among survivors, and adverse neurological outcomes at two years of age or later2. To determine the adverse effects of lactoferrin supplementation for prophylaxis of neonatal sepsis and/or NECWhen data were available, we analyzed the following subgroups.1. Gestational age < 32 weeks and 32 to 36 weeks2. Birth weight < 1000 g (extremely low birth weight (ELBW) infants) and birth weight < 1500 g (very low birth weight (VLBW) infants)3. Type of feeding: breast milk versus formula milk SEARCH METHODS: We used the search strategy of the Cochrane Neonatal Review Group (CNRG) to update our search in December 2016. We searched the databases Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PREMEDLINE, Embase, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), as well as trial registries and conference proceedings.

SELECTION CRITERIA

Randomized controlled trials (RCTs) evaluating oral lactoferrin at any dose or duration to prevent sepsis or NEC in preterm neonates.

DATA COLLECTION AND ANALYSIS

Review authors used standard methods of the CNRG.

MAIN RESULTS

This review includes six RCTs. Trial results show that lactoferrin supplementation to enteral feeds decreased late-onset sepsis (typical risk ratio (RR) 0.59, 95% confidence interval (CI) 0.40 to 0.87; typical risk difference (RD) -0.06, 95% CI -0.10 to -0.02; number needed to treat for an additional beneficial outcome (NNTB) 17, 95% CI 10 to 50; six trials, 886 participants; low-quality evidence) and NEC stage II or III (typical RR 0.40, 95% CI 0.18 to 0.86; typical RD -0.04, 95% CI -0.06 to -0.01; NNTB 25, 95% CI 17 to 100; four studies, 750 participants; low-quality evidence). Lactoferrin supplementation did not have an effect on "all-cause mortality" (typical RR 0.65, 95% CI 0.37 to 1.11; typical RD -0.02, 95% CI -0.05 to 0; six studies, 1041 participants; low-quality evidence).Lactoferrin supplementation to enteral feeds with probiotics decreased late-onset sepsis (RR 0.27, 95% CI 0.12 to 0.60; RD -0.13, 95% CI -0.19 to -0.06; NNTB 8, 95% CI 5 to 17; one study, 321 participants; low-quality evidence) and NEC stage II or III (RR 0.04, 95% CI 0.00 to 0.62; RD -0.05, 95% CI -0.08 to -0.03; NNTB 20, 95% CI 12.5 to 33.3; one study, 496 participants; low-quality evidence), but not "all-cause mortality" (low-quality evidence).Lactoferrin supplementation to enteral feeds with or without probiotics decreased bacterial and fungal sepsis but not CLD or length of hospital stay (low-quality evidence). Investigators reported no adverse effects and did not evaluate long-term neurological outcomes and PVL.

AUTHORS' CONCLUSIONS

Evidence of low quality suggests that lactoferrin supplementation to enteral feeds with or without probiotics decreases late-onset sepsis and NEC stage II or III in preterm infants without adverse effects. Completed ongoing trials will provide data from more than 6000 preterm neonates, which may enhance the quality of the evidence. Clarification regarding optimal dosing regimens, types of lactoferrin (human or bovine), and long-term outcomes is needed.

Bioactive properties of milk proteins in humans: A review

Many studies have demonstrated that milk protein consumption has benefits in terms of promoting human health. This review assesses the intervention studies which have evaluated potential health enhancing effects in humans following the ingestion of milk proteins. The impact of milk protein ingestion has been studied to asses their satiating, hypotensive, antimicrobial, anti-inflammatory, anticancer, antioxidant and insulinotropic properties as well as their impact on morphological modifications (e.g., muscle and fat mass) in humans. Consistent health promoting effects appear to have been observed in certain instances (i.e., muscle protein synthesis, insulinotropic and hypotensive activity). However, controversial outcomes have also been reported (i.e., antimicrobial, anti-inflammatory, anticancer and antioxidant properties). Several factors including interindividual differences, the timing of protein ingestion as well as the potency of the active components may explain these differences. In addition, processing conditions have been reported, in certain instances, to affect milk protein structure and therefore modify their bioactive potential. It is thought that the health promoting properties of milk proteins are linked to the release of bioactive peptides (BAPs) during gastrointestinal digestion. There is a need for further research to develop a more in-depth understanding on the possible mechanisms involved in the observed physiological effects. In addition, more carefully controlled and appropriately powered human intervention studies are required to demonstrate the health enhancing properties of milk proteins in humans.

Late-onset neonatal sepsis: recent developments

The incidence of neonatal late-onset sepsis (LOS) is inversely related to the degree of maturity and varies geographically from 0.61% to 14.2% among hospitalised newborns. Epidemiological data on very low birth weight infants shows that the predominant pathogens of neonatal LOS are coagulase-negative staphylococci, followed by Gram-negative bacilli and fungi. Due to the difficulties in a prompt diagnosis of LOS and LOS-associated high risk of mortality and long-term neurodevelopmental sequelae, empirical antibiotic treatment is initiated on suspicion of LOS. However, empirical therapy is often inappropriately used with unnecessary broad-spectrum antibiotics and a prolonged duration of treatment. The increasing number of multidrug-resistant Gram-negative micro-organisms in neonatal intensive care units (NICU) worldwide is a serious concern, which requires thorough and efficient surveillance strategies and appropriate treatment regimens. Immunological strategies for preventing neonatal LOS are not supported by current evidence, and approaches, such as a strict hygiene protocol and the minimisation of invasive procedures in NICUs represent the cornerstone to reduce the burden of neonatal LOS.

Oral lactoferrin for the prevention of sepsis and necrotizing enterocolitis in preterm infants

BACKGROUND

Lactoferrin, a normal component of human colostrum and milk, can enhance host defense and may be effective in the prevention of sepsis and necrotizing enterocolitis (NEC) in preterm neonates.

OBJECTIVES

Primary objective To assess the safety and effectiveness of oral lactoferrin in the prevention of sepsis and NEC in preterm neonates. Secondary objectives1. To determine the effects of oral lactoferrin used to prevent neonatal sepsis and/or NEC on duration of positive-pressure ventilation, development of chronic lung disease (CLD) or periventricular leukomalacia (PVL), length of hospital stay to discharge among survivors, and adverse neurological outcomes at two years of age or later.2. To determine the adverse effects of oral lactoferrin in the prophylaxis of neonatal sepsis and/or NEC.When data were available, we analyzed the following subgroups.1. Gestational age < 32 weeks and 32 to 36 weeks.2. Birth weight < 1000 g (extremely low birth weight (ELBW) infants) and birth weight < 1500 g (very low birth weight (VLBW) infants).3. Type of feeding: breast milk versus formula milk.

SEARCH METHODS

We used the search strategy of the Cochrane Neonatal Review Group (CNRG) and updated our search in July 2014. We searched the databases Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PREMEDLINE, EMBASE, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), as well as trials registries and conference proceedings.

SELECTION CRITERIA

Randomized controlled trials (RCTs) evaluating oral lactoferrin at any dose or duration to prevent sepsis or NEC in preterm neonates.

DATA COLLECTION AND ANALYSIS

Review authors used standard methods of the CNRG.

MAIN RESULTS

Four RCTs are included in this review. Oral lactoferrin supplementation decreased late-onset sepsis (typical risk ratio (RR) 0.49, 95% confidence interval (CI) 0.32 to 0.73; typical risk difference (RD) -0.09, 95% CI -0.14 to -0.04; number needed to treat for an additional beneficial outcome (NNTB) 11, 95% CI 7 to 25; four trials, 678 participants, moderate-quality evidence), NEC stage II or greater (typical RR 0.30, 95% CI 0.12 to 0.76; typical RD -0.05, 95% CI -0.08 to -0.01; NNTB 20, 95% CI 12.5 to 100; two studies, 505 participants, low-quality evidence), and "all-cause mortality" (typical RR 0.30, 95% CI 0.12 to 0.75; typical RD -0.05, 95% CI -0.08 to -0.01; NNTB 20, 95% CI 12.5 to 100; two studies, 505 participants, low-quality evidence).Oral lactoferrin supplementation with a probiotic decreased late-onset sepsis (RR 0.27, 95% CI 0.12 to 0.60; RD -0.13, 95% CI -0.19 to -0.06; NNTB 8, 95% CI 5 to 17; one study, 321 participants, low-quality evidence) and NEC stage II or greater (RR 0.04, 95% CI 0.00 to 0.62; RD -0.05, 95% CI -0.08 to -0.03; NNTB 20, 95% CI 12.5 to 33.3; one study, 496 participants, low-quality evidence), but not "all-cause mortality."Oral lactoferrin with or without probiotics decreased fungal sepsis but not chronic lung disease or length of hospital stay (from one study, low-quality evidence). No adverse effects were reported. Long-term neurological outcomes or periventricular leukomalacia was not evaluated.

AUTHORS' CONCLUSIONS

Evidence of moderate to low quality suggests that oral lactoferrin prophylaxis with or without probiotics decreases late-onset sepsis and NEC stage II or greater in preterm infants without adverse effects. Completion of ongoing trials will provide evidence from more than 6000 preterm neonates and may enhance the quality of the evidence. Clarifications regarding optimum dosing regimens, type of lactoferrin (human or bovine), and long-term outcomes are still needed.

Antimicrobial protein and Peptide concentrations and activity in human breast milk consumed by preterm infants at risk of late-onset neonatal sepsis

Objective

We investigated the levels and antimicrobial activity of antimicrobial proteins and peptides (AMPs) in breast milk consumed by preterm infants, and whether deficiencies of these factors were associated with late-onset neonatal sepsis (LOS), a bacterial infection that frequently occurs in preterm infants in the neonatal period.

Study design

Breast milk from mothers of preterm infants (≤32 weeks gestation) was collected on days 7 (n = 88) and 21 (n = 77) postpartum. Concentrations of lactoferrin, LL-37, beta-defensins 1 and 2, and alpha-defensin 5 were measured by enzyme-linked immunosorbent assay. The antimicrobial activity of breast milk samples against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Streptococcus agalactiae was compared to the activity of infant formula, alone or supplemented with physiological levels of AMPs. Samples of breast milk fed to infants with and without subsequent LOS were compared for levels of AMPs and inhibition of bacterial growth.

Results

Levels of most AMPs and antibacterial activity in preterm breast milk were higher at day 7 than at day 21. Lactoferrin was the only AMP that limited pathogen growth >50% when added to formula at a concentration equivalent to that present in breast milk. Levels of AMPs were similar in the breast milk fed to infants with and without LOS, however, infants who developed LOS consumed significantly less breast milk and lower doses of milk AMPs than those who were free from LOS.

Conclusions

The concentrations of lactoferrin and defensins in preterm breast milk have antimicrobial activity against common neonatal pathogens.

Enteral nutrition and infections: the role of human milk

Human milk (HM) is known as the best nutrition for newborns and support the optimal growth of infants, providing essential substances, nutrients, bioactive and immunologic constituents. HM also grants a favorable microbial colonization with attendant priming/maturation of the gut. The bioactive and immunologic elements of HM demonstrated to protect offspring against infection and inflammation and contribute to immune maturation. Some of these elements are being investigated in order to be used to ameliorate formula milk. A formula milk similar to breast milk may help neonatal gut to build a microbiota near to the one of the breast fed infants, improving the neonate's protection against pathogens. The aim of this review is to summarize the most significant bioactive constituents of HM that own natural anti-infectious properties and contribute to neonatal immune defense.

The effect of UV-C pasteurization on bacteriostatic properties and immunological proteins of donor human milk

Background

Human milk possesses bacteriostatic properties, largely due to the presence of immunological proteins. Heat treatments such as Holder pasteurization reduce the concentration of immunological proteins in human milk and consequently increase the bacterial growth rate. This study investigated the bacterial growth rate and the immunological protein concentration of ultraviolet (UV-C) irradiated, Holder pasteurized and untreated human milk.

Methods

Samples (n=10) of untreated, Holder pasteurized and UV-C irradiated human milk were inoculated with E. coli and S. aureus and the growth rate over 2 hours incubation time at 37°C was observed. Additionally, the concentration of sIgA, lactoferrin and lysozyme of untreated and treated human milk was analyzed.

Results

The bacterial growth rate of untreated and UV-C irradiated human milk was not significantly different. The bacterial growth rate of Holder pasteurized human milk was double compared to untreated human milk (p<0.001). The retention of sIgA, lactoferrin and lysozyme after UV-C irradiation was 89%, 87%, and 75% respectively, which were higher than Holder treated with 49%, 9%, and 41% respectively.

Conclusion

UV-C irradiation of human milk preserves significantly higher levels of immunological proteins than Holder pasteurization, resulting in bacteriostatic properties similar to those of untreated human milk.

Influence of iron status on risk of maternal or neonatal infection and on neonatal mortality with an emphasis on developing countries

Infection is a major cause of neonatal death in developing countries. This review investigates whether host iron status affects the risk of maternal and/or neonatal infection, potentially contributing to neonatal death, and summarizes the iron acquisition mechanisms described for pathogens causing stillbirth, preterm birth, and congenital infection. In vitro evidence shows that iron availability influences the severity and chronicity of infections that cause these negative outcomes of pregnancy. In vivo evidence is lacking, as relevant studies of maternal iron supplementation have not assessed the effect of iron status on the risk of maternal and/or neonatal infection. Reducing iron-deficiency anemia among women is beneficial and should improve the iron stores of babies; moreover, there is evidence that iron status in young children predicts the risk of malaria and, possibly, the risk of invasive bacterial diseases. Caution with maternal iron supplementation is indicated in iron-replete women who may be at high risk of exposure to infection, although distinguishing between iron-replete and iron-deficient women is currently difficult in developing countries, where a point-of-care test is needed. Further research is indicated to investigate the risk of infection relative to iron status in mothers and babies in order to avoid iron intervention strategies that may result in detrimental birth outcomes in some groups of women.

Neonatal immune adaptation of the gut and its role during infections

The intestinal tract is engaged in a relationship with a dense and complex microbial ecosystem, the microbiota. The establishment of this symbiosis is essential for host physiology, metabolism, and immune homeostasis. Because newborns are essentially sterile, the first exposure to microorganisms and environmental endotoxins during the neonatal period is followed by a crucial sequence of active events leading to immune tolerance and homeostasis. Contact with potent immunostimulatory molecules starts immediately at birth, and the discrimination between commensal bacteria and invading pathogens is essential to avoid an inappropriate immune stimulation and/or host infection. The dysregulation of these tight interactions between host and microbiota can be responsible for important health disorders, including inflammation and sepsis. This review summarizes the molecular events leading to the establishment of postnatal immune tolerance and how pathogens can avoid host immunity and induce neonatal infections and sepsis.